High frequency oscillator



Jan. 16, 1934. H. ROTHE El AL 1,943,627

HIGH FREQUENCY OSCILLATOR Filed May 19. 1930 gzzzm FE! l. g A 4) T J ILINVENTORS HORST ROTHE BY HANS OTTO ROOSENSTEIN ATTORNEY Patented Jan.16, 1934:

1,943,627 HIGH FREQUENCY OSCILLATOR Horst Rothe 4 Claims.

It has been found that .in the case of oscillator circuits for extremelyhigh frequencies it is very diificult in practice to preclude radiofrequency waves from the D. C. leads brought to the apparatus. In orderto obviate this difiiculty the leads carrying plate and grid currentsare suitably brought to a point in the oscillation circuit whose radiofrequency potential to ground is as low as possible. In order that atthe same point the plate and the grid currents may be connected, one wayout would be to insert in the circuit such a large blocking condenser Cb(Fig. 1) that the flow or" radio frequency will practically not beinfluenced. However, especially where very high frequencies are dealtwith it is practically impossible in this scheme to pre-determine thepoint where the circuit is to be cut in such a manner that owing to theexistent division of potential by way of Cgk and Ca}; the internalcapacities of the tubes will present a minimum potential in the circuit.Once the cut or separation has been established, a change in location,i. e., a shift in tapping points for supplying D. C. potentials is butdifiicultly accomplishable.

In the accompanying drawing Figure 1 is given by way of explanation ofthe present invention described in detail in connection with Figure 2.

Now, according to this invention the inconvenience already indicated, isobviated by that the oscillation circuit throughout its entire length ismade to consist of two conductors 2, 4 (Fig. 2) presenting such acapacity in relation to each other that the entire system, looked atfrom a viewpoint of radio frequency, may be conceived as a singleconductor. One suitable embodiment consists in that the oscillating loopis built up of two or more copper bands or strips being separated fromone another by interposed layers of mica, for instance. Along thesebands the taps 6, 8 for grid and plate current are effected by the aidof a double slide adjustable in the course of operations.

The arrangement here disclosed offers this further merit that the twofilament leads 10 conjointly with the grid and the plate D. C. leads maybe wound upon a choke-coil 14. The beginning of the latter is connectedby way of four blocking condensers K K to the shielding box 16 or cageof the set. This mode of grounding can be established again at anotherpoint of the choke-coil (K -K Fig. 2). It is recommendable to so choosethis second point that the two parts will exhibit practically no jointovertones. If proper care is taken in this respect it will be and HansBerlin, Germany, assignors to Telefunken Gesellschait fur DrahtloseTelegraphic m. b. EL, Berlin, Germany, a corporation of GermanyApplication May 19, 1930, Serial No. 453,449,

- and in Germany June 1, 1929 Gtto Roosenstein,

possible to establish and provide perfect screening or shielding of theset which is otherwise but hard to insure in the case of ultra-shortwaves.

We claim as our invention:

1. A high frequency oscillatory circuit having, in combination, anelectron discharge device comprising an anode and a grid, an oscillatorycircuit comprising two open ended, closely adjacent conductors, one ofsaid conductors being connected with the grid, and the other of saidconductors with the anode, the open end of the conductor connected tothe anode being near the connection point of the other open endedconductor to the grid, and the open end of the conductor connected tothe grid being near the end of the open ended conductor connected to theanode, said two conductors presenting such a high distributed capacityin relation to each other that they can be regarded as a singleconductor from a radio frequency standpoint, a source of grid potentialand a source of anode potential, and leads extending from said sourcesto the open ended conductors connecting with said grid and anode, saidleads being adjustable with resoect to the ends of said conductors.

2. A high frequency oscillatory circuit having, in combination, anelectron discharge device comprising an anode, cathode and a grid, anoscillatory circuit comprising two open ended, closely adjacentconductors, one of said conductors be- 85 ing connected to said grid,and the other one of said conductors being connected to said anode, theopen end of the conductor connected to said anode being near theconnection point of the other open ended conductor to the grid, and theopen end of the conductor connected to the grid being near the end ofthe open ended conductor connected to the anode, a source of gridpotential, a source of anode potential, and a source of cathodepotential, leads extending from said sources of grid and anode potentialto theconductors connecting with said grid and anode, and leadsextending from said cathode to said source of cathode potential, a chokecoil, said supply leads for said cathode, anode and grid being wrappedupon said one choke coil and said choke coil being grounded by way ofcondensers.

3. An oscillator having an anode a cathode and a control electrode, anopen-ended conductor connected to said control electrode, an open-endedconductor connected to said anode, said conductors lying adjacent eachother and relatively parallel to each other, the open end of theconductor connected to said control electrode being adjacent theconnection point of the open-ended 110 conductor connected to the anode,the open end of the conductor connected to said anode being adjacent theconnection point of said open-ended conductor connected to said controlelectrode, a source of anode potential, a source of control electrodepotential, and adjustable means for coupling said sources through saidopen-ended conductors to said anode and control electrode at pointsintermediate the ends of said conductors, and individual condensers forsaid anode and control electrodes, the armatures on one side of saidcondensers being connected to said adjustable coupling means and thearmatures on the other side of said condensers being in circuit withsaid cathode.

4. Apparatus having, in combination, an electron discharge devicecomprising an anode, cathode and control electrode, an open-endedconductor connected to said control electrode, an open-ended conductorconnected to said anode, said conductors lying adjacent to each otherand all relatively parallel to each other, the open end of the conductorconnected to said control electrode being adjacent to the connectionpoint of the open-ended conductor connected to the anode, the open endof the conductor connected to said anode being adjacent the connectionpoint of said open-ended conductor connected to said control electrode,a source of anode potential, a source of control electrode potential,individual connections between said anode and control electrode sourcesof potential and points on said conductors intermediate their ends, saidconnections being adjustable on said conductors, a source of cathodepotential connected to both legs of said cathode, individual condensersarranged between said adjustable connections and ground, and additionalcondensers between both legs of said cathode and ground.

HORST ROTHE. HANS OTTO ROOSENSTEIN.

